ParagonIE_Sodium_File::sign_core32( string $filePath, string $secretKey ): string

1193    private static function sign_core32($filePath, $secretKey)1194    {1195        $size = filesize($filePath);1196        if (!is_int($size)) {1197            throw new SodiumException('Could not obtain the file size');1198        }1199 1200        $fp = fopen($filePath, 'rb');1201        if (!is_resource($fp)) {1202            throw new SodiumException('Could not open input file for reading');1203        }1204 1205        /** @var string $az */1206        $az = hash('sha512', self::substr($secretKey, 0, 32), true);1207 1208        $az[0] = self::intToChr(self::chrToInt($az[0]) & 248);1209        $az[31] = self::intToChr((self::chrToInt($az[31]) & 63) | 64);1210 1211        $hs = hash_init('sha512');1212        self::hash_update($hs, self::substr($az, 32, 32));1213        /** @var resource $hs */1214        $hs = self::updateHashWithFile($hs, $fp, $size);1215 1216        $nonceHash = hash_final($hs, true);1217        $pk = self::substr($secretKey, 32, 32);1218        $nonce = ParagonIE_Sodium_Core32_Ed25519::sc_reduce($nonceHash) . self::substr($nonceHash, 32);1219        $sig = ParagonIE_Sodium_Core32_Ed25519::ge_p3_tobytes(1220            ParagonIE_Sodium_Core32_Ed25519::ge_scalarmult_base($nonce)1221        );1222 1223        $hs = hash_init('sha512');1224        self::hash_update($hs, self::substr($sig, 0, 32));1225        self::hash_update($hs, self::substr($pk, 0, 32));1226        /** @var resource $hs */1227        $hs = self::updateHashWithFile($hs, $fp, $size);1228 1229        $hramHash = hash_final($hs, true);1230 1231        $hram = ParagonIE_Sodium_Core32_Ed25519::sc_reduce($hramHash);1232 1233        $sigAfter = ParagonIE_Sodium_Core32_Ed25519::sc_muladd($hram, $az, $nonce);1234 1235        /** @var string $sig */1236        $sig = self::substr($sig, 0, 32) . self::substr($sigAfter, 0, 32);1237 1238        try {1239            ParagonIE_Sodium_Compat::memzero($az);1240        } catch (SodiumException $ex) {1241            $az = null;1242        }1243        fclose($fp);1244        return $sig;1245    }